Neuroimaging

Question 1

Which methods of structural imaging are there?

Answer 1

• Dissection: Brain out of skull
• CT scan: x-rays of thin slices - clinically useful, different tissue absorbs, put together as 3d
• MRI scan: magnetic field aligns protons -> protons back to normal -> measure radio waves re-emitted -> high resolution pictures
• DTI scan: (the ‘pretty picture’) looks at nerve fibre tracts (white matter), shows connections through the way water diffuses

Question 2

Which methods of functional imaging are there?

Answer 2

• PET/SPECT: Radioactive tracers in bloodstream (measures positron particles emitted) - good eg for specific drugs
• fMRI: measures BOLD (oxygenated blood) response, good for mapping
• EEG: Measures small voltage on scalp, good for timing by ERPs (event related potential)
• MEG: Measures magnetic field around head due to change in brain’s electric field, better localisation than EEG